A combined theoretical and experimental study of the stereochemical behavior of (31)P-(1)H spin-spin coupling constants has been performed in the series of trivinylphosphine and related trivinylphosphine oxide, sulfide and selenide. Theoretical energy-based conformational analysis of the title compounds performed at the MP2/6-311G** level reveals that each of the four compounds of this series exists in the equilibrium mixture of five true-minimum conformers, namely s-cis-s-cis-s-cis, s-cis-s-cis-gauche, syn-s-cis-gauche-gauche, anti-s-cis-gauche-gauche and gauche-gauche-gauche, which were taken into account in the conformational averaging of (31)P-(1)H spin-spin couplings calculated at the second-order polarization propagator approach/aug-cc-pVTZ-J level of theory. All (31)P-(1)H spin-spin coupling constants involving phosphorus and either of the vinyl protons are found to demonstrate a marked stereochemical dependences with respect to the geometry of the coupling pathway and internal rotation of the vinyl group around the P-C bond which is of major importance in the stereochemical studies of the unsaturated phosphines and phosphine chalcogenides.
Traditional methods for C–P bond formation via direct addition of P–H species to unsaturated compounds are usually implemented in the presence of base and metal catalysts or radical initiators in various organic solvents. During the last five years, a novel efficient and general catalyst/initiator- and solvent-free version of the hydrophosphination and hydrophosphinylation of multiple C–C bonds with H-phosphines and their chalcogenides has begun to develop and it is attracting growing attention. This approach corresponds to the recently emerged pot-, atom-, and step-economy (PASE) green paradigm. This review covers the literature on the synthesis of useful and in-demand organophosphorus compounds via catalyst- and solvent-free addition of P–H species to alkenes and alkynes.1 Introduction2 Addition of Secondary Phosphines to Alkenes3 Hydrophosphinylation of Alkenes with Secondary Phosphine Chalcogenides3.1 Oxidative Addition of Phosphine Oxides to Vinyl Sulfides3.2 Addition of Secondary Phosphine Sulfides and Phosphine Selenides to Alkenes3.3 Addition of Secondary Phosphine Sulfides and Phosphine Selenides to Divinyl Chalcogenides3.4 Hydrophosphinylation of Alkenes with Secondary Phosphine/Chalcogen Pair (Three-Component Reactions)4 Addition of Secondary Phosphines to Alkynes5 Addition of Secondary Phosphine Chalcogenides to Alkynes6 Conclusion
A series of tertiary phosphine sulfides and selenides have been synthesized in excellent yields (88‐99%) via a three‐component reaction between secondary phosphines, electron‐rich alkenes (styrene, vinyl chalcogenides), and elemental sulfur or selenium, proceeding under solvent‐free conditions (80‐82°C, 4–44 h). The interaction occurs via initial oxidation of secondary phosphines with elemental sulfur or selenium followed by noncatalyzed anti‐Markovnikov addition of the generated R2P(E)H (E = S, Se) species to alkenes to afford the corresponding adducts with high chemo‐ and regioselectivity.
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